EP0249526A1 - Machine for coating a flat element by applying and fusing a thermoplastic film - Google Patents

Abstract

1. Machine for the plastic coating of a flat document (21) by application and fusion of a thermoplastic film (22, 24) on at least one of the two faces of a document of this type by passing successively through a heating station and a cooling station while these documents are clamped between two individual metallic pressing plates (3, 4) which ensure the displacement of these latter over the entire length of the machine and form part of two series of such plates arranged in succession so as to form two closed loops placed one above the other, each work station respectively for heating and cooling being constituted by a press (1 or 2), the jaws of which are capable of clamping between them two pressing plates (3, 4) located one above the other with the document (21) placed between them and the film or films (22, 24) which are intended to constitute the plastic coating sheets, suitable control and synchronization means for producing intermittent feed motion of the two loops formed by the two series of pressing plates (3 and 4) so as to ensure that each pair of complementary plates forming part of both series remains within each work station during a sufficiently long stationary period, characterized in that, in each series of pressing plates (3, 4), the successive plates are independent of each other and each of these plates (3, 4) is freely articulated on chains (5 and 6) or the like which are placed on each side so as to constitute the means for driving these two closed-loop pressing-plate belts.

Description

The present invention relates to the plasticization of documents or other elements of flat shape by application and fusion of a film of thermoplastic material on at least one of the two faces of such an element.

Such plasticization is commonly used to protect and / or enhance all kinds of documents, for example photographs or advertising posters, maps, etc. However, this technique is also applied to items other than paper or similar documents.

To achieve this type of plastic coating, a sheet of thermoplastic material should be placed on at least one of the two sides of the document to be treated and a metal plate, generally a shiny stainless steel plate, placed thereon , then to press the assembly by making it undergo, successively a first heating treatment to obtain the softening and the melting of the plastic film by heating, then, a second cooling treatment to achieve the stabilization of the assembly in the 'state obtained.

In old plastification installations, the two operations thus provided are carried out in two separate devices comprising each a clamping press and one of which also includes heating means, while the other is equipped with cooling means. However, this way of operating requires the transfer of documents from one processing device to another, which has a certain number of drawbacks and in particular that of increasing the duration of the processing time.

To speed up the laminating operation of a series of documents, it has already been proposed to process them in machines designed to ensure that they are processed "continuously".

Thus, Swiss patent 376,652 describes a machine which comprises two metal pressing strips forming two closed circuits arranged one opposite the other and which have two strands in contact. The arrangement is such that the documents to be processed can be introduced between these two strands at one end of the machine by being placed between two plastic films which also engage between the two pressing strands of the two metal strips. continue. Thus these two bands carry with them both each of the documents to be processed and the two plastic films to pass this assembly successively inside a heating station, ensuring the softening of the plastic films, then to inside a cooling station stabilizing each document processed.

European patent application EP 134.820 describes a machine corresponding to the same basic design.

However, machines of this kind have two drawbacks due to which it is not possible to obtain satisfactory plasticization of the documents to be processed.

The first of these drawbacks is that the use of continuous pressing strips does not does not allow to obtain the same result as in the case where each document to be treated would be placed inside a separate press, on the one hand during the softening treatment by heating and on the other hand during the stabilization treatment by cooling. Indeed, the conditions of pressing by continuous bands are much less good and cannot be exerted perfectly on the entire surface of the documents to be treated. Furthermore, the clamping pressures cannot be different in the case of one and the other of the two operations to be carried out. However, during the first softening treatment, it suffices to exert a low clamping pressure, while during the stabilization treatment, a very high pressure must be applied to crush the plastic film or films against the document to be treated. Moreover, the pressures to be expected in both cases can vary in a proportion from 1 to 10.

The second major drawback of the above-mentioned machines lies in the fact that with continuous clamping bands, it is not possible to obtain precise treatment conditions in each of the work stations and that, moreover, these bands undergo detrimental deformations due to the successive heating and cooling undergone by the different parts of these strips. Regarding the first point it should be noted that the parts of the clamping bands located in the heating station transmit their heat to the neighboring parts which are then inside the cooling station. This therefore disturbs the cooling conditions. With regard to the second point, it is quite obvious that the heating and cooling of very close parts of the same strip lead to deformations of the latter, so that it can no longer be applied perfectly by its entire surface on the corresponding plastic film.

This is why the present invention aims to achieve a laminating machine designed to perform "continuously" the processing of a series of documents, but without the disadvantages of current machines of the type mentioned above.

To this end, the subject of the invention is a machine for plasticizing a document of flat shape by applying and fusing a film of thermoplastic material on at least one of the two faces of such a document by passing successively in a heating station and a cooling station while these documents are clamped between pressing means ensuring their training over the entire length of the machine, characterized in that:
the means for clamping the documents to be processed consist of two series of individual metal pressing plates which are freely articulated on drive chains or the like which are closed on themselves so as to form, with these two series of plates, two closed loops arranged one above the other,
- At the place of each of the work stations, respectively for heating and cooling, there is provided a press, the jaws of which are capable of clamping between them two pressing plates arranged one above the other, with the document placed between them and the film or films intended to constitute the laminating sheets,
- appropriate control and synchronization means ensuring the intermittent advance of the two loops formed by the two series of pressing plates so that each pair of complementary plates, belonging to one and the other series, remains for one Sufficient parking time inside each workstation.

Thus, in the present machine, each document to be processed is trapped between two complementary pressing plates and these accompany it throughout the duration of passage of this document inside this machine. As the pressing plates of each series are independent of each other, there is no detrimental interaction of one on the other. Furthermore, the documents are pressed under the best conditions in each of the workstations - heating or cooling - since this is carried out by means of separate presses.

In an advantageous embodiment of the present machine, the mobile pressing plates of the two upper and lower series are suspended from their articulation axis and those of the lower series are provided with ballasting elements ensuring their maintenance in a horizontal position .

• La figure 1 est une vue schématique en coupe longitudinale d'une machine de plastification selon l'invention.
• La figure 2 est une vue schématique en plan de dessus de la partie inférieure de cette machine, la partie supérieure de celle-ci ayant été omise pour simplifier le dessin et permettre une meilleure compréhension de celui-­ci.
• La figure 3 est une vue en coupe transversale selon la ligne III-III de la figure 1, mais à échelle différente.
• La figure 4 est une vue schématique et partielle en élévation de côté de l'extrémité d'entrée de la présente machine.
• La figure 5 est une vue en coupe longitudinale de l'une des plaques mobiles de pressage de la série inférieure.

However, other features and advantages of the present machine will become apparent from the following description of an exemplary embodiment thereof. This description is given with reference to the attached drawing for information only and in which:

• Figure 1 is a schematic longitudinal sectional view of a plasticizing machine according to the invention.
• Figure 2 is a schematic top plan view of the lower part of this machine, the upper part thereof having been omitted to simplify the drawing and allow a better understanding thereof.
• Figure 3 is a cross-sectional view along line III-III of Figure 1, but on a different scale.
• Figure 4 is a schematic and partial view in side elevation of the inlet end of the present machine.
• Figure 5 is a longitudinal sectional view of one of the movable pressing plates of the lower series.

As already indicated, the present machine comprises two working presses designated by the general references 1 and 2 in FIG. 2, the first of them being assigned to the plastification operation proper and the other to the subsequent operation stabilization. These two presses are integrated one after the other inside the present machine.

There are also provided two series of movable pressing plates, namely a lower series of plate 3 and an upper series of plate 4. The plates of one and the other of these two series are attached to means of drive which impart to them a horizontal working trajectory during which each plate of one of the series is opposite a plate of the other and passes with it inside the two presses 1 and 2.

In the example shown, the means for driving the individual pressing plates of each series consist of two chains 5 and 6 closed on themselves and which are arranged on either side of the corresponding plates. These chains pass at their ends on toothed wheels 7 and 8 for deflection and / or drive. These two groups of movable chains are arranged one above the other as shown in FIG. 1 and the arrangement is such that the chains of the lower group and those of the upper group have two strands 5a and 6a arranged parallel close to each other. one on the other, on both sides of a horizontal plane XY, which constitutes the plan of circulation of the documents to process inside the machine.

The gear wheels for driving the chains of the two groups rotate in opposite directions so that these strands 5a and 6a of the drive chains move forward according to arrow F, from the input end 9 of the machine to its outlet end 10. This also corresponds to the working path of the pressing plates of one and the other of the two series.

These pressing plates are freely mounted articulated on the corresponding drive chains 5 and 6, and this around horizontal axes 11 carried by these chains. These axes are arranged directly above the median transverse line of each plate. Thus, under the simple effect of their own weight, the plates 4 of the upper series are kept horizontally above the corresponding axes.

As for the movable plates 3 of the lower series, they carry, on each side, a horizontal bar 12 for ballasting as shown in FIG. 5. These bars are fixed by means of the fingers 13, the length of which is such that these bars are arranged below the level of the hinge pins 11 of the corresponding plate. Thus, the plates 3 of the lower series are constantly maintained in a horizontal position, even at both ends of the machine, as it appears in FIGS. 1 and 4.

However, guide rails 14 can be additionally provided, in particular at one and the other ends of the machine (see FIG. 4).

To prevent the documents and films to be processed from being subjected to too sudden temperature variations, each pressing plate is formed by the combination of two metal plates 15 and 16 between which is interposed a sheet 17 of rubber or other similar material capable of serving as a kind of damper for the transfer of temperature from one of the plates to the other and thus to delay this transfer in order to spread it over time to avoid too sudden variations (see figure 5).

The two working presses 1 and 2 have a conventional structure for presses used for operations of the type in question. Each of them includes two mobile pressing plates 1a, 1b, and 2a, 2b respectively, actuated by hydraulic cylinders 18. But of course in each press, a single plate can be mobile, the other consisting of a fixed base. The plates 1a and 1b of the first press include suitable heating means, for example electrical resistors 19. But these means could just as easily consist of a heating liquid circuit. As for the plates of the press 2, they comprise cooling means, for example a cooling liquid circuit. Opposite the inlet end 9 of the machine, there is provided a horizontal plate 20 intended to serve as a support for each document 21 to be processed, before its introduction into this machine. On this plate is extended a first thermoplastic film 22 delivered from a feed roller 23. This film then extends inside the machine over the entire length thereof.

A second thermo-plastic film 24, delivered from a feed roller 25, is also unwound over the entire length of the machine above the documents to be processed. However, deflection rollers 26 keep this film spaced at a certain distance above the location where each document 21 to be processed is placed on the tray 20 against the lower film 22. But the upper film is then itself guided sure each document to be processed, before being introduced into the machine, by means of a return roller 27.

Shortly before this, a device 28 is provided for eliminating the static electricity that this film may contain. Under these conditions, only the lower film 22 comprises static electricity, which has the effect that when it is put in place each document 21 is immobilized on this film and does not risk being subjected to an untimely movement during the application of the upper film 24.

Before being deposited on the tray 20, the documents to be processed are arranged in the form of a stack 29 in a food store or other similar device. They are then deposited one after the other by a supply device of the type used in the printing industry and which is shown diagrammatically by the movable operating arm 30 in FIGS. 1 and 2. However, it it would also be possible to provide any other suitable device, for example a loading robot.

Next to the output 10 of the machine, there is provided a cutting device intended to separate one from the other the documents processed therein. In Figure 1, this device is shown schematically by two movable knives 31 arranged transversely. However, it is obvious that the control device thus provided could be of a different design. Thus it could be a "shaped" cutting device, that is to say capable of carrying out, in a single operation, a cutting all around each document.

The stepwise advance of the two pairs of pressing plates, which accompany each document to be processed during its stay inside the machine, is ensured by a control device determining the desired parking times in the two presses of work. Of course, the operation of these is also synchronized with this stepwise advance movement. Furthermore, the assembly can be controlled by a control box 32 also controlling the cutting device provided at the outlet. This control box is synchronized with another control box 33 controlling the supply device, these two boxes being under the control of a central general control device 34 which may include a programming system, as well as all the desired adjustment members.

The operation of this machine is as follows :

Each document 21 to be treated is deposited at the desired time on the preparation plate 20 on which the film 22 already extends. This deposit is ensured in a precise position by the feed device shown diagrammatically by the movable arm 30.

During a new advance of the lateral drive chains 5 and 6, the lower film 22 is pulled forward and it carries with it the document 21 which was previously deposited on it. This document then comes into position 21a below an upper film 24. From this moment, this document is trapped between the two films 22 and 24.

Then after an intermediate stop position, the document in question enters the input end 9 of the machine and it is thus brought to engage between a lower plate 3 and an upper pressing plate 4. From the corresponding position 21c, this document is always trapped between the two corresponding plates which accompany it during its entire movement inside the machine.

In the following position 21d, the document in question is placed inside the first press 1 and it parks there the time required for the operation of softening and melting of thermoplastic films. This processing time can be of the order of 30 to 90 seconds, for example 40 seconds.

When this first operation has been completed, the document in question is drawn into position 21e at the location of the second press 2. In the latter, it undergoes the stabilization operation by cooling between the plates of this press. Of course, the duration of this operation is exactly the same as the previous one since during this time the following document for its part undergoes the first plasticization operation at the location of the press 1.

Finally, after the movable pressing plates have moved away from the document considered at the outlet end 10 of the machine, it reaches the cutting station 31, after one or more intermediate positions.

It is important to note the important role that certain characteristics of the present machine play for the proper functioning of the latter. Thus, the "floating" mounting of the mobile pressing plates allows them to be placed properly on either side of each document to be processed and then to ensure the proper execution of the pressing of each document. during the two operations carried out at the location of the presses 1 and 2. As for the mounting of these pressing plates on the lateral drive chains 5 and 6, it has the advantage that these plates have sufficient mobility in the vertical direction to be able to undergo the pressing operations in one and the other of the two processing presses.

The example of use of the present machine, which is described above, relates to the plasticization of a document between two films of thermoplastic material. However, this machine could also be used for laminating only one side of such a document. In which case, only the lower film 22 would remain, so that the face to be laminated should be placed against this film.

It should also be remembered that the machine according to the invention can be used for the laminating of flat-shaped elements, other than documents on paper. Thus, it could be used to laminate thermo-plastic cards or metal plates, or even plates carrying printed or engraved electronic circuits, etc. Furthermore, in the case of elements or documents of restricted areas, it would be possible to laminate several of these simultaneously. In fact, the supply device 30 is preferably designed so as to be able to deposit several elements of restricted dimensioning side by side.

However, the present machine could also be used for the manufacture of memory cards. In such a case, the very body of such a card could be formed from a plastic film interposed between the two films 22 and 24 and which would include, at the location of the location of each card, a obviously intended to receive a magnetic memory element, this being then trapped between the two films 22 and 24 after the plasticization operation.

• a) d'une part le serrage de chaque document à traiter entre deux plaques distinctes de pressage,
• b) d'autre part le serrage de ces plaques et de chaque document correspondant par des presses distinctes dans l'un et l'autre des deux postes de travail.

Compared to previous laminating machines by continuous treatment, the present machine has two essential advantages, namely:

• a) on the one hand, the clamping of each document to be processed between two separate pressing plates,
• b) on the other hand, the tightening of these plates and of each corresponding document by presses separate in each of the two workstations.

With regard to the first point, it is obvious that the use of two distinct series of pressing plates makes it possible to avoid the drawbacks inherent in machines comprising continuous pressing strips. Thus the individual pressing plates can be applied perfectly by their entire surface on the documents to be processed since there is no interaction of one plate on the other since they are articulated freely on the chains. training and that they are also relatively flexible. Furthermore, there is no untimely communication of heat from one pair of pressing plates to another.

With regard to the second point, it should be noted that the use of separate presses in each work station makes it possible to ensure precise pressing conditions and especially different values of tightening at the location of the one and the other work stations, the pressure having to be much more considerable at the place of the cooling station than at the place of the heating station.

Of course the machine according to the invention can be the subject of various variant embodiments. Thus, it may possibly include a larger number of processing presses to subdivide the two plasticization and stabilization operations. Indeed, for the first operation it is possible to provide a first preheating press and a second maximum heating. Likewise for the second operation, it is possible to provide a first press for the start of cooling and a second for the completion thereof.

Claims (5)

1. Machine for laminating a document of flat shape by applying and fusing a film of thermoplastic material on at least one of the two faces of such a document by passing successively through a heating station and a cooling station while these documents are clamped between pressing means ensuring their training over the entire length of the machine, characterized in that:
the means for clamping the documents to be processed consist of two series of individual metal pressing plates (3 and 4) which are freely articulated on drive chains (5 and 6) or the like which are closed in on themselves so to form, with these two series of plates, two closed loops arranged one above the other,
- at the place of each of the work stations, respectively for heating and cooling, there is provided a press (1 or 2), the jaws of which are capable of clamping two pressing plates (3 and 4), arranged between them 'one above the other, with the document placed between them and the film or films intended to constitute the laminating sheets,
- appropriate control and synchronization means ensuring the intermittent advance of the two loops formed by the two series of pressing plates (3 and 4) so that each pair of complementary plates, belonging to both series , remains for a sufficient period of parking inside each work station. 2. Laminating machine according to claim 1, characterized in that the mobile pressing plates (3) of the two upper and lower series, are suspended from their articulation axis (11) and those of the lower series are provided with ballasting elements (12) ensuring their maintenance in a horizontal position. 3. Machine according to one of the preceding claims, characterized in that for the plasticization of a flat element (21) on its two faces, two coils (23 and 25) are provided for supplying thermoplastic films as well that different deflection rollers bringing the two corresponding films (22 and 24) on either side of each element (21) to be treated, and this before the engagement of the assembly between movable pressing plates (3 and 4 ). 4. Machine according to claim 3, characterized in that opposite the inlet end (9) of this machine, there is provided a plate (20) for depositing each document to be processed by a device (30) feed and in that the upper film (24) is kept apart from this plate by deflection rollers (26) to be subsequently brought above each element to be treated (21) after its deposition on the lower film (22 ). 5. Machine according to claim 4, characterized in that there is provided a device for eliminating static electricity on the upper film (24) before its application on each element (21) to be treated.

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